JPS59589A - Multi-stage centrifugal pump - Google Patents

Abstract

PURPOSE:To enable to obtain a high lifting head with a small flow rate of fluid, by disposing a plurality of multi-stage centrifugal pumps satisfying the restriction of strength in parallel with each other, and providing pipes through which fluid is passed in series and a mechanism for driving the pumps at their outer shafts by a single driving means. CONSTITUTION:Two multi-stage centrifugal pumps 2, 3 of the same structure are mounted on a base (not shown) in parallel with each other, and six impellers 6, 6 are fixed to each of main shafts 4, 5 of the pumps 2, 3 restricted by the flow rate of fluid in the manner of satisfying the strength of the shafts 4, 5. The main shafts 4, 5 are driven from the outside by the driving force of a motor (not shown) via a gear means 8. With such an arrangement, when the motor is set into operation with a valve 11a in a feed pipe 11 being closed after the pressure indicated by a pressure gauge 11b is raised, fluid supplied from a supply pipe 9 is supplied under pressure to required places via the feed pipe 11 with its pressure being raised successively by the impellers 6, 6 of the pumps 2, 3.

Description

DETAILED DESCRIPTION OF THE INVENTION One aspect of the present invention is a centrifugal multi-stage bop with a small flow bar lift.

Generally, when designing a centrifugal multistage pump with a small flow rate and high head, the design points (flow rate, total head, rotation speed, required N,
Once P, S, and Hl are determined, the impeller inlet diameter is determined. If the design flow rate is small in the above.

In order to obtain good pump efficiency, it is necessary to reduce the diameter of the five-impeller. Along with this, the diameter of the main shaft passing through the center of the impeller is also limited.

By the way, a plurality of impellers are attached to the main shaft, and since these rotate at high speed, if the impeller is too long, it will bend. For this reason, the length of the main shaft is limited by its diameter, and the number of impellers that can be attached is limited by that length. That is, the small quicksand centrifugal multi-stage pump has the disadvantage that the lift is limited depending on the flow rate.

In view of the above circumstances, an object of the present invention is to provide a centrifugal multistage pump that can freely obtain a high head with a small flow rate. The pumps are arranged in parallel, and are provided with piping so that fluid flows through each pump in series, and are equipped with a mechanism for driving each pump with an outer shaft by a single drive machine.

The present invention will be explained below with reference to the drawings.

1 and 2 show an embodiment of a centrifugal multistage pump according to the present invention, and reference numeral 1 in the figures indicates a base. Two identical centrifugal multistage pumps (hereinafter referred to as pumps) 2 and 3 are attached to the base 1 in parallel. and n etc. pump 2
．． The flow rate of 3 is small.

Six impellers 6 are attached to each of the main shafts 4 and 5, but when used alone, each impeller cannot obtain the specified lift f'
From the strength of the Lzutsutamata main shafts 4 and 5, the required 12
Six impellers 6... are attached to each pump so as to satisfy the main shaft strength, which is limited by the reduced flow rate. The main shafts 4, 5 of the pumps 2, 3 are externally driven at the same speed by the rotational driving force of the motor 7 via a variable speed gear (C gear) 8.

A liquid supply pipe 9 is attached to the inlet 2a of the pump 2. Further, the discharge port 2b of the pump 2 and the inlet port 3a of the pump 3 are communicated with each other by a pipe 10. A liquid delivery pipe 11 is attached to the discharge port 3b of the friend pump 3. This feed pipe 11 includes a pulp lla and a pressure gauge 1.
1b is attached.

In Fig. 2, 12... indicates a gland or bearing for receiving the main shafts 4, 5, +3.14 indicates a coupling, and the arrow indicates the direction of liquid passage.

Next, the operation of the centrifugal multistage pump constructed as above will be explained.

First, the pulp lla of the feed pipe 11 is closed and the motor 7 is driven. After the pressure gauge Jlb indicates pressure rises, pulp ll
Let a be open. The liquid supplied from the supply pipe 9 is sequentially pressurized by the impellers 6 of the pumps 2, 3, and is pumped through the delivery pipe 11 to the necessary locations.

In the above case, the two and three pumps also satisfy the strength limit, and it is possible to achieve the required head with just one pump.

Although the above explanation has been about a two-shaft pump, it is possible to configure a multi-shaft centrifugal multi-stage pump by selecting a variable speed two-gear device.Next, the design procedure will be shown and the present invention will be explained in more detail. explain.

Calculating the strength of the main shaft from the design point If it is not possible to add y from the impeller up to the shift plate, and if a 17-stage impeller is required to obtain the design head, two 7-stage centrifugal multi-stage pumps are used as pumps. If the pump head is insufficient and three pumps are used, then the pump head is excessive and it is found that it is most economical to use three centrifugal multistage pumps with six stages.

-! FIG. 3 shows another embodiment of the present invention, in which the casings of the pump 2.3 are fixed together into one casing and shifter, and two rotor units are incorporated into the casing. A suitable internal flow path 10' is provided inside the piping JOO to constitute a composite centrifugal multi-stage pump. In the figure, the same parts as those in FIG. 2 are given the same reference numerals, and the explanation thereof will be omitted.

As described above, the centrifugal multi-stage pump according to the present invention is constructed by combining a plurality of centrifugal multi-stage pumps that satisfy the strength restriction conditions for small flow rates, so that It is something that can be dealt with freely.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the multistage centrifugal pump according to the present invention. Figure 1 is a plan view, Figure 2 is a plan view for explaining the operation, and Figure 3 is a plan view. FIG. 1 is a plan view of a centrifugal multistage pump showing another embodiment of the present invention; 1...Base; 2...Centrifugal multistage pump;
2a...Inlet port, 2b...Discharge port% 3.
...Centrifugal multistage pump, 3a...Inlet,
3b...Discharge port, 4...Main shaft of pump 3,
5... main shaft of pump 3, 6... impeller, 7
...Motor, 8...Gear device, 9...
Liquid supply pipe, 10...Communication pipe, 10'...
Internal flow path, 11-...Transmission piping, 111IL...
・Pulp, 11b...Pressure gauge, 12...Bearing or gland, 13.14...Coupling.

Claims (1)

[Claims] fil Based on a small flow rate, high head centrifugal multistage pump,
Multiple centrifugal multi-stage pumps with the number of stages within the limit determined by the strength of the main shaft are arranged in parallel, piping is provided so that the fluid flows through each pump in series, and each pump is driven by a single drive machine on the outer shaft. A centrifugal multistage pump with a driving mechanism. (2) The centrifugal multistage pump according to claim 1, wherein the plurality of centrifugal multistage pumps have main shafts provided in parallel within the same casing, and an internal flow path is configured within the casing.